American spokesperson Mary Frances Fagan said flight 1544 headed to Reagan's National Airport left the gate at 6:42 p.m. As it was getting into position to take off around 7:15 p.m., the MD 80 hit an icy patch and slid sideways off the runway onto the grass.
An airline spokesman in Fort Worth said none of the 54 passengers or five crew members were injured and all were taken by bus back to the terminal.
The plane was blocking the way to the runway and Chicago Aviation Department spokesman Greg Cunningham said officials with the National Transportation Safety Board had to inspect the aircraft before it could be moved.
The spokesman called the incident "nothing spectacular" and said the plane is still in place until workers can assess if the landing gear is in the mud and if the plane needs to be lifted from the location.
American Airlines said it was working to get all the passengers from Flight 1544 onto other flights to Reagan National.